include (multi) point

[mattijn]

This PR is the start of including Point and MultiPoint as input types.
It takes more time than a Sunday evening (maybe another Sunday evening).

There is now a separation between bookkeeping of arcs (originating from LineString, MultiLineString, Polygon, MultiPolygon and GeometryCollection) and bookkeeping of coordinates (originating from Point and MultiPoint).

The difficulty is to include the bookkeeping of coordinates at the places when it is needed in the same structure as the bookkeeping of arcs.

Still some thinking to do in the hash mapping and single point transform computation

Not finished yet.

[mattijn]

This is fixed.

Within the Topojson format the coordinates of type Point and MultiPoint are not stored in the top-key arcs object, but remain within the objects. This is quite cumbersome since quantization does apply to the coordinates as well.

Resolved internally by storing the coordinates on top-key level as shapely objects till the topology phase and only resolved into lists within the to_dict()/to_alt()/etc functions.

This is different compare the arcs which are resolved within the hashmap class.

Add multi different tests in the various classes since there were eventually changes in more or less all classes

Working example:

import topojson as tp

data = [
    {
        "type": "MultiPoint",
        "coordinates": [[0.5, 0.8], [1.0, 1.1]]     
    },    
    {
        "type": "Point",
        "coordinates": [1.1, 0.5]    
    },      
    {
        "type": "Polygon",
        "coordinates": [[[0, 0], [0.5, 0], [0.5, 0.5], [0, 0.5], [0, 0]]]
    }

]

topo = tp.Topology(data, topoquantize=True)
topo.to_alt(color='geometry.type:N')